1. Field of the Invention
This invention relates to a novel hydroxamic acid derivative and a method of preparing metoclopramide using the same.
2. Description of the Prior Art
Many methods are reported by preparing metoclopramide, i.e., N-(2-diethylaminoethyl)-2-methoxy-4-amino-5-chlorobenzamide useful as a antiemetic and an improving agent for digestion. Most of these methods use p-aminosalicylic acid as the starting material. More specifically, N-(2-diethylaminoethyl)-2-methoxy-4-amino-5-chlorobenzamide is prepared through each of the reaction steps including the methoxylation of the hydroxyl group at the 2-position of the benzene ring of the starting material, the chlorination at the 5-position of the benzene ring and the amidation of the carbonyl group with N,N-diethylethylenediamine.
One representative example of these conventional method is as follows; ##STR3##
However, these conventional methods require complicated treatments in reaction, separation and purification of the above described steps and expensive reagents.